Analytical or diagnostic or therapeutic procedures are crucial in many functions in the modern society. One of the most common is the diagnostic procedures performed at health care institutions (e.g. hospitals) with the purpose to determine if a patient has a selected disease. For example, elevated concentration of the prostate specific antigen (PSA) in male blood is an indication of ongoing prostate cancer in the patient. Other analytical or diagnostic or therapeutic procedures include, but are not limited to, the diagnosis of cattle prior to slaughter in order to produce safe food, diagnostic procedures in veterinary sciences with the purpose of treating sick animals, targeted radiotherapy of tumors in animal or humans, the detection of pathogens or toxins in food or feed stuff, the determination of the concentration of nutritional supplements (e.g. vitamins) in processed food or feed stuff, the detection of hazardous chemicals in the environment and the like.
One particular method for diagnosis is positron emission tomography (PET). PET can depict the location of the radioactive decay of positron emitting nuclides. Diagnostic PET procedures are developed for a multitude of diseases, most notably for cancers (as evident in the report “18F-FET PET Compared with 18F-FDG PET and CT in Patients with Head and Neck Cancer.” by Pauleit D, Zimmermann A, Stoffels G, Bauer D, Risse J, Fluss M O, Hamacher K, Coenen H H, Langen K J. published in Journal of Nuclear Medicine. 2006 February; 47(2):256-261, which is incorporated by reference herein). In all cases, the object under investigation must be contacted with a bi-functional species. Firstly, the species should interact with features of or be part of the function to be diagnosed. Secondly, the species should carry positron emitting nuclides. In case the object is a human and the purpose is to diagnose a possible cancer disease, the species could be an antibody specifically recognizing tumor cells, where the antibody has been labeled with fluorine-18 (a nuclide known to emit positrons), carbon-11 or another nuclide emitting positrons.
Another method for diagnosis is single photon emission computed tomography (SPECT). SPECT can depict the location of the radioactive decay of certain gamma emitting nuclides, such as technetium-99 or iodine-123, in a similar fashion to PET, as evident in the report “Early dynamic 201T1 SPECT in the evaluation of brain tumours.” by Sugo N, Yokota K, Kondo K, Harada N, Aoki Y, Miyazaki C, Nemoto M, Kano T, Ohishi H, Seiki Y. published in Nuclear medicine communications. 2006 February; 27(2): 143-9, which is incorporated by reference herein.
One example of therapy is the so-called targeted radiotherapy (described in the report “Advances in radioimmunotherapy in the age of molecular engineering and pretargeting.” by Sharkey R M, Goldenberg D M. published in Cancer Investigation. 2006; 24(1):82-97, which is incorporated by reference herein), used mainly in treatment of selected cancers. In such therapy, aggressively radiating nuclides are immobilized to molecules that selectively bind to cancer cells. Upon injection of the radiating molecules in the blood stream of an animal or a human, the molecules will accumulate on cancer cells and be present in low concentration elsewhere in the body. Thus, the radiation source is brought very close to the cancerous tissue, thereby maximizing the radioactive dose to the cancer cells and sparing the remaining body from radiation.
The treatment can also be performed with molecules directing the immune defense to the therapeutic target or by conjugates of target specific molecules and other functions causing damage to specific cells.
One major problem with analytic and diagnostic and therapeutic procedures in general and PET in particular is that the quality of the result is very much dependent on the quality of the species used in the procedure. In some cases, the species are fragile molecules that may alter in function and reliability in transit from manufacturer to end user. Species suitable for PET is one example, where it is known that some of the commonly used positron emitting nuclides have half lives of hours (fluorine-18 has a half life of 110 minutes). Species suitable for targeted radiotherapy is a second example, where the emitting nuclides also have short half lives, such as iodine 131 with a half life of 8 days. It is therefore not certain that the quality control of the species performed at the site of manufacturing is valid when the species arrives at the end user site.
This invention describes a simple and rapid method for quality control of species or targets or intermediates at different steps in the production of species or targets at the end user site which would increase the reliability of commonly performed analytical and diagnostic procedures.